Beartype 0.10.0 broken in python 3.9.1

Hello, I noticed that since the new update, we can no longer import beartype within python 3.9.1. This is the error I get:

>>> import beartype
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/jlidin/.local/share/virtualenvs/test-beartype/lib/python3.9/site-packages/beartype/__init__.py", line 129, in <module>
    from beartype._decor.main import beartype
  File "/home/jlidin/.local/share/virtualenvs/test-beartype/lib/python3.9/site-packages/beartype/_decor/main.py", line 71, in <module>
    ) -> Union[BeartypeableT, BeartypeConfedDecorator]:
  File "/home/jlidin/.local/share/pyenv/versions/3.9.1/lib/python3.9/typing.py", line 262, in inner
    return func(*args, **kwds)
  File "/home/jlidin/.local/share/pyenv/versions/3.9.1/lib/python3.9/typing.py", line 339, in __getitem__
    return self._getitem(self, parameters)
  File "/home/jlidin/.local/share/pyenv/versions/3.9.1/lib/python3.9/typing.py", line 451, in Union
    parameters = _remove_dups_flatten(parameters)
  File "/home/jlidin/.local/share/pyenv/versions/3.9.1/lib/python3.9/typing.py", line 231, in _remove_dups_flatten
    return tuple(_deduplicate(params))
  File "/home/jlidin/.local/share/pyenv/versions/3.9.1/lib/python3.9/typing.py", line 205, in _deduplicate
    all_params = set(params)
TypeError: unhashable type: 'list'

This was tested with a clean virtual environment and only beartype installed. It did work with python 3.10.2 however. Is the new version only compatible with python 3.10?

[leycec]

With profuse apologies and a sweaty brow, I’m closing this kinda awkwardly. Python 3.9.1 is broke. No one should use broke Python. But someone is. But someone using broke Python is outside our wheelhouse.

Maybe there’s a demonstrably good reason for someone to use broke Python? If so, angrily bang on that Reopen button and we’ll tactfully revisit this. Until then, please upgrade your Python to something less visibly broke.

May the fist-bumping bear be with you always. 🤛 🐻 👍

[leycec]

…we can no longer import beartype within python 3.9.1.

ohnoes

The sky is falling and we have only this flimsy microlight wingsuit.

Is the new version only compatible with python 3.10?

Thank Guido, no. We still retain full backward and forward compatibility with Python 3.6.0–3.10.2. At least, we thought we did. 😬

Our GitHub Actions-hosted continuous integration (CI) workflow tends to only test on the most recently patch version of each CPython release. For the Python 3.9 release cycle, this means CPython 3.9.9. CPython 3.9.1 is rather crusty around the ears at this point and possibly a security concern.

Still, we absolutely want to support all possible CPython versions. This includes CPython 3.9.1. In this case, the CPython 3.9.1-specific implementation of the standard typing module appears to suffer critical defects with respect to PEP 448-style unions and child type hints containing lists. </sigh>

zomg

Oh, yes. This is actually a known CPython 3.9.1 issue (#42965) subsequently resolved in CPython 3.9.2. Badness erupts! Older CPython being fundamentally broken kinda makes us a bit less inclined to want to try resolve this on our end – especially as the only means of doing so seems to be revert to deprecated typing.Callable[...] type hints under Python 3.9.1. I shake my bald head.

Given that your typing implementation is critically cracked up, is there any chance you’d be willing to update to a newer CPython 3.9 release, @joelid?

I had encountered warnings having only partial stack traces (and therefore not pointing at the offending line of code) in python 3.9.7…

That… also doesn’t sound good. When you get a spare moment, please drop us a traceback bomb and we’ll guillotine that bug with aplomb. 🪦